Proceedings of the Annual Meeting of the Cognitive Science Society

Many theories of conceptual organization assume the existence of some form of mental similarity metric (Medin and Schaffer, 1978; Hintzman and Ludlum, 1980; Nosofsky, 1988; Shepard, 1987; Kruschke, 1992, among others.) In the domain of categorization, such theories have been called "similarity-based" (Murphy and Medin, 1985). Criticism of similarity-based the- stories has led to a call for "theory-based" models of categorization (Murphy and Medin, 1985; Rips, 1989; Barsalou, 1991; Medin, 1989). Theory-based views remain somewhat vague, however. In this paper I outline a schema-based theory of conceptual organi- zation. T h e model depends on the notion of amen - tal similarity metric but makes use of connectionist learning principles to develop a conceptual organiza- tion that solves a problem faced by purely similarity- based models of categorization. I discuss the rela- tionship of this theory to similarity-based and theory- based accounts.